1. Field of the Invention
The present invention is related to a flask or container which is preferably used for drying biological materials. More specifically, embodiments of the present invention provide a flask for receiving biological materials, and method for treating or processing the biological materials while contained in the flask.
2. Description of the Prior Art
Dried biological materials are becoming increasingly useful in agriculture, biotechnology and medicine. For instance, freeze-dried human blood products, vaccines and the like are already in use, or are proposed to be in use, in clinical settings for both animal and human applications. In the field of biotechnology, biosensors have wide spread applications. In all such cases, long term storage under sterile conditions, and often under unfavorable environmental circumstances, is a requirement.
Conventional devices in the market do not optimally provide drying of biological materials under sterile conditions, while allowing for certain desired contamination-free processing of the biological materials under defined conditions, such as during drying, storage and re-hydration. More particularly, because biological materials show much improved survival if they are exposed to water vapor prior to immersion in liquid water, it is desired to pre-hydrate biological samples with water vapor without contaminating the biological samples.
A patentability investigation was conducted to determine the state of the art with respect to solving problems of contamination while processing biological materials during drying, storage and re-hydration, and the following U.S. Patents were discovered: U.S. Pat. No. 4,232,453 to Edelmann; U.S. Pat. No. 4,275,511 to Parkinsen, et al.; U.S. Pat. No. 4,966,469 to Fraser, et al.; U.S. Pat. No. 5,154,007 to Piunno, et al.; U.S. Pat. No. 5,689,595 to Sutherland, et al.; and U.S. Pat. No. 6,122,836 to Tenedini, et al.
U.S. Pat. No. 4,232,453 to Edelmann discloses a tray for holding a biological specimen and a submersible container for freeze-drying the specimen. A heating element is taught for melting a synthetic resin for embedding the specimen therein.
U.S. Pat. No. 4,275,511 to Parkinsen, et al. discloses an evaporator/sublimator flask having a straight sided cylinder, preferably made of borosilicate glass tubing of sufficient wall thickness to prevent implosion when subjected to a high vacuum. The straight sided cylinder is open at one end and sealed at the other. An elastomer cap is disposed over the open end of the cylinder.
U.S. Pat. No. 4,966,469 to Fraser, et al. discloses a flask for freeze-drying. A positioning device engages the top of the flask and comprises a generally circular stopper having an opening. An annular tube extends through the stopper and into the flask. A thermocouple is coiled around the lower part of the annular tube.
U.S. Pat. No. 5,154,007 to Piunno, et al. discloses an apparatus and describes a method for distillation drying of one or more biological samples. The apparatus includes a retaining assembly, a vacuum assembly, a cooling assembly, a monitoring assembly and a control assembly for actively regulating the temperature and pressure conditions of biological tissue so that biological samples may be dried without damage.
U.S. Pat. No. 5,689,895 to Sutherland, et al. discloses a device for positioning a probe (e.g., a temperature sensor) in a flask for freeze-drying. The device includes a stopper secured to an open end of the flask. The stopper has a center opening and at least one radial opening spaced from the center opening. The radial opening allows for fluid communication between inside and outside of the flask when the stopper is secured to the open end of the flask. The center opening receives a guide tube which extends into the flask and receives the probe.
U.S. Pat. No. 6,122,836 to Tenedini, et al. discloses a freeze-drying apparatus and associated lyophilization procedures employing vapor flow detection and/or vacuum control for monitoring and control of a lyophilization process. The vapor flow detector (e.g., a windmill sensor) is disposed to monitor vapor flow from product undergoing lyophilization.
None of the foregoing patents teach a flask, device or container which permits drying (freeze-drying, air-drying, foam drying) of biological materials under sterile conditions and which allows for processing under defined conditions during drying, storage and re-hydration. Therefore, what is needed and what has been invented is a flask and method which overcomes the contamination deficiencies of the prior art. What is more specifically needed and what has been invented is a flask for drying (e.g., freeze-drying) substances under sterile conditions, and method for processing a substance under sterile conditions, including drying, storage, and rehydration. In the method for processing, the flask is placed on a shelf of a freeze-drying and re-hydration apparatus where substances contained in the flask are freeze-dried and re-hydrated without contamination.